1. Field of Invention
This invention relates to a system for visually inspecting flat reflective parts such as metal panels for defects, which may include scratches, gouges, holes inclusions and such, by scanning the panel with a stripe of light, recording the gray-scale values of reflected light for an array of pixels covering the panel, and processing the gray-scale values for the array of pixels using high speed vision processing equipment to identify the defects. More particularly, the invention is directed to such a system in which modular vision processing boards with limited area coverage are used to inspect larger panels on-line and in which the data indicative of a defect is reduced to speed processing.
2. Background Information
Many flat parts such as for example copper laminate panels used in making .printed circuit boards must be inspected after manufacture to identify defective units. Typical defects in these copper laminate panels include scratches, gouges, dents over certain dimensions, pin-point holes and inclusions, any of which could impair the performance of a printed circuit board using such a panel. The presence of a few minor scratches, dents, et cetera may be tolerated, however, a large number of even such minor blemishes is cause for rejection. To date, the inspection of such panels has been accomplished by workers visually scanning each panel. Thus, inspection has been labor intensive and, therefore expensive. It is also prone to variability from one inspector to another.
It is therefore an object of the invention to provide a reliable, reasonably priced automated system for inspecting panels and other flat reflective parts.
It is a more specific object of the invention to provide such an automated inspection system which generates a pixel array of gray-scale values of light reflected from the inspected panel and which utilizes modular vision processing apparatus to generate data representing selective defects in the panels.
It is a further object of the invention to provide such system in which modular vision processing equipment with limited area coverage can be used to inspect panels of larger area.
It is an additional object of the invention to provide such a system incorporating techniques which reduce the data indicative of the selected defects to reduce processing time and the capacity of the apparatus required to perform the inspection on-line.